Technical Yearbook 2023

APRI L

Depth filtration with continuous dosing of filter aid.

The impact of cross-flow filtration on wine filterability By Charl Theron

Cross-flow filtration or tangential flow filtration has become popular among winemakers. It offers single pass filtration without the need for intervention or significant operator supervision. It is, however, expensive and offers only one filtration grade option. Depth versus cross-flow filtration In most wine filters, the wine is passed through a filter element until blockage of the filter medium occurs. The

wine flow is only in one direction. In cross-flow filters, the wine is passed parallel to the filter medium, and due to the application of pressure, the filtrate is forced through the filter medium. The filtrate flow is consequently tangential to the wine flow direction. The filter medium for in-depth filtration can be in different forms like diatomaceous earth, sheets, lenticular or case cartridges. Although these are different filter types, the principle of depth filtration applies to all of them, where particles are entrapped and retained in the filter medium. Depth filters consequently have an element of thickness or depth. Sheet filters and lenticular filters (which are only a different format of sheet filters) have a filter medium of

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TECHNICAL YEARBOOK 2023